首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7614篇
  免费   341篇
  2020年   111篇
  2019年   132篇
  2018年   196篇
  2017年   227篇
  2016年   243篇
  2015年   195篇
  2014年   175篇
  2013年   1962篇
  2012年   220篇
  2011年   243篇
  2010年   209篇
  2009年   247篇
  2008年   254篇
  2007年   199篇
  2006年   166篇
  2005年   94篇
  2004年   112篇
  2003年   105篇
  2002年   96篇
  2001年   142篇
  2000年   114篇
  1999年   101篇
  1998年   74篇
  1997年   70篇
  1996年   70篇
  1995年   82篇
  1994年   65篇
  1993年   83篇
  1992年   57篇
  1991年   74篇
  1990年   59篇
  1989年   71篇
  1988年   61篇
  1987年   77篇
  1986年   64篇
  1985年   84篇
  1984年   92篇
  1983年   96篇
  1982年   78篇
  1981年   71篇
  1980年   82篇
  1979年   70篇
  1978年   83篇
  1977年   83篇
  1976年   99篇
  1975年   55篇
  1974年   57篇
  1973年   52篇
  1972年   47篇
  1971年   41篇
排序方式: 共有7955条查询结果,搜索用时 281 毫秒
991.
This paper presents the chemical characterization of 79 fragments of Archaic and Hellenistic fine‐grained pottery from archaeological sites in Messina, Catania, Lentini and Siracusa (Sicily). The sherds were classified as ‘calcidian’, ‘banded’, ‘unvarnished’ and ‘black varnished’ pottery. The major and trace elements identified by X‐ray fluorescence (XRF) were statistically elaborated using the method proposed by J. Aitchinson in 1986 for the analysis of compositional data. From cluster analyses using element/SiO2 log‐ratios, it was possible to group the pottery found in Catania, Lentini and Siracusa into highly linked clusters. Conversely, the Messina pottery was divided into two clearly distinct groups. With the aim of identifying any possible mineralogical differences between the two Messina groups, Fourier transform infrared (FT–IR) absorption measurements were made, showing only quantitative differences in plagioclase and muscovite. The specific groups of pottery with restricted chemical compositions are considered to be of local production, also on the basis of archaeological and petrographic evidence.  相似文献   
992.
Work hard, play hard: selling Kelowna, BC, as year-round playground   总被引:1,自引:1,他引:0  
A keen interest in place making and place selling is widespread in contemporary society. While the bulk of academic research has focused on studying the restructuring of large urban conglomerates, places beyond the exploding metropolis, by comparison, have received little attention, especially when it concerns Canadian landscapes. In an attempt to study the particularities of place making in contemporary smaller, more isolated communities—hinterlands—this work analyses the city of Kelowna, in British Columbia, Canada. We argue that historically Kelowna, a small rural community specialising in ranching, forestry and fruit production, since the early 1980s, has been re-imagined and re-designed, on the one hand as an all-year playground and as an innovative frontier for high-tech industries; on the other hand, this post-Fordist reinvention contains a discourse of 'whiteness', one that entices by packaging 'place' in terms of 'sameness' and 'familiarity'. In contrast to large cosmopolitan post-industrial cities, hinterland-type cities are invented, sought and lived as geographies cleared from the 'elements' that make cities 'unsafe'.  相似文献   
993.
One of the paradoxical effects of the 7 July bombings in London was to expose the ambivalence in the British government's attempt to wage war on terror by forcefully prosecuting war against those who resort to jihad abroad, actively participating in coalitions of the willing whether in Afghanistan or Iraq, while affording some of Islamism's key ideologists and strategists a high degree of latitude in the United Kingdom itself. This indicates a number of contradictions in official policy that simultaneously recognizes the globalized threat from violent Islamic militancy while, under the rubric of multiculturalism, tolerating those very strains of Islamist radicalism, some of which draw upon the interdependent and transnational character of conflict, to render the UK vulnerable to those very same violent forces. Consequently, the British authorities displayed a studied indifference towards this developing transnational phenomenon both during the 1990s and in some respects even after the London bombings. To explore the curious character of the government's response to the Islamist threat requires the examination of the emergence of this radical ideological understanding and what it entails as a reaction to modernization and secularism in both thought and practice. The analysis explores how government policies often facilitated the non-negotiable identity politics of those promoting a pure, authentic and regenerated Islamic order both in the UK and abroad. This reflected a profound misunderstanding of the growing source and appeal of radical Islam that can be interpreted as a consequence of the slow-motion collision between modernity in its recent globalized form and an Islamic social character, which renders standard western modernization theory, and indeed, the notion of a 'social science' itself, deeply questionable.  相似文献   
994.
Abstract. Numerous models propose an income‐distribution/growth linkage, but the empirical evidence is ambiguous and depends on the regression approach. Mixed findings are not unexpected if there are differing short‐ and long‐term responses. Approaches utilizing cross‐sectional variation primarily reflect long‐run effects, whereas those using time‐series variation primarily reveal short‐run effects. This study reconciles these issues using U.S. state data. After allowing for short‐ and long‐run responses and for separate effects between the tails and middle of the distribution, the consistent pattern is the middle‐class share and overall inequality are positively related to long‐run growth. However, the short‐run income‐distribution response is less clear.  相似文献   
995.
As far as the law of preservation of matter and the existence of ether are concerned, Kant, Lomonossow and Lavoisier had very similar views. Nevertheless, according to historical evidence they worked out their theories never taking each other's results for granted. Whereas it is well known that Lavoisier did not base his experiments on the former ones by Lomonossow, it has been argued that Kant based his philosophy of nature on Lavoisier's experiments. I try to show here, that Kant had his philosophy of nature done, prior to Lavoisier's Elements of Chemistry. Further that the only one to have been able to influence Kant was not Lavoisier but Lomonossow. But Kant never mentioned Lomonossow. There is strong evidence that the similarity of views in Kant, Lomonossow and Lavoisier is not due to any kind of interaction between them. This also holds of the (same) mistakes, which Kant and Lomonossow made. The only substantial difference is that Kant thought, that some laws of nature may be logically inferred without experiments.  相似文献   
996.
Twenty-one samples of likely Roman, likely Islamic and unknown common ware from the archaeological site of Thamusida (Rabat, Morocco) were analysed in order to anchor selected types of pottery to a limited time span and, possibly, to a production area and technology. Analytical techniques were thermoluminescence, optical microscopy, scanning electron microscopy and X-ray fluorescence. The results arising from this research are definitely useful for the study of the site of Thamusida as well as for all researchers involved in archaeological and archaeometrical research in Morocco. Chronologies proposed on a typological base have been denied twice: a likely Islamic cup dates back to the second century a.d.; vice versa, a stewpot, framed into the Roman period, resulted to be an eighth century a.d. production. Moreover, the identification of an eighteenth century ceramic production is of outstanding importance, as it characterises a completely unknown production. Regarding the production area, four samples of both Roman and Islamic periods have been recognised as local productions of Thamusida.  相似文献   
997.
As evidence concerning human mobility during the transition to agriculture in central Europe, we present the results of strontium isotope analysis of human skeletons from the Neolithic village of Vaihingen, Germany. We find significantly more ‘non‐local’87Sr/86Sr values from humans buried in a Neolithic ditch surrounding Vaihingen than from those buried within the settlement. These results fit with previous studies showing a correlation between burial circumstances and strontium isotope signatures from LBK cemeteries of southwestern Germany ( Price et al. 2001 ; Bentley et al. 2002 ). A pilot study of Neolithic animal teeth from Vaihingen suggests that either ‘local’87Sr/86Sr signatures were more variable than the analysed human bones suggest, or that these domestic animals themselves were mobile, perhaps ranged by mobile pastoralists.  相似文献   
998.
U‐series dating was used to determine the growth rate of a feldspar‐to‐clay weathering rind in a mid‐Holocene Cascade–Olcott tradition andesite core, and luminescence dating (last exposure to sunlight) was used to date fine‐grained feldspars scraped from the surfaces of similar buried artefacts from a 14C‐sediment‐dated archaeological site (45KI464) on the wet western slope of the Cascade Mountains of Washington. For U‐series dating, we measured 226Ra excess (226Ra excess =226Ra –230Th) in five stratigraphic depth controlled rind scrapings. 238U, 232Th and 230Th were counted by alpha spectrometry, and 226Ra and 210Pb were counted by gamma spectrometry on each sub‐sample.  相似文献   
999.
Fragments of late medieval highly decorated Falke‐group stoneware have been found in excavations all over central and northern Europe. The distribution of the finds points to an origin in Saxony, but the exact centre of production is still unknown. Therefore, a set of samples has been analysed with Neutron Activation and the data compared with Saxon reference groups. The results point to production in a single workshop. The data can be clearly distinguished from all reference groups in our databank. However, the most similar group is that of Zittau, Saxony. Also, one sherd, which is typologically very similar to the Falke group, and which was made in Zittau, suggests that production was based there.  相似文献   
1000.
The study of technology transfer in pottery production to the periphery of the Mycenaean world has been addressed by considering two different areas, southern Italy and central Macedonia. Technological features such as ceramic paste, decoration and firing have been determined for different ceramic groups established according to provenance criteria. The studies of technology and provenance have been performed following an archaeometric approach, using neutron activation analysis, petrographic analysis, X‐ray diffraction and scanning electron microscopy. The results have revealed the existence of two different models. On the one hand, southern Italy seems to exhibit a more organized pottery production, which follows a Mycenaean‐like technology, while in central Macedonia production is probably more varied, being based in part on the technology of the local tradition.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号